The present invention relates in general to microfilm reader, and, more particularly, to microfilm reader/printers.
The field of information retrieval has developed rapidly in recent years, and there is much art in this area. However, known devices have several drawbacks. The primary drawback is caused by the failure of known devices to properly optically couple a microfilm reader to a rotating printing process in a manner which is independent of the magnification ratio of the reader.
Secondly, the known devices require complete disappearance of the viewed image to effect printing. A user's concentration is thereby interrupted.
Some prior art devices, such as those devices disclosed in U.S. Pat. Nos. 3,871,766 and 4,023,897, have means for maintaining conjugate length. However, there is no known device having means for holding a slit image path at right angles to an intercepted array of light throughout a complete scan sequence. More broadly, there is only one known device relating to scanning on the image side of a projection lens; however, in this device, disclosed in U.S. Pat. No. 3,841,753, the image is not formed on a rotating drum.
Thus, there is need for a device which not only maintains a conjugate length path constant, but also maintains a slit image path at right angles to an intercepted beam of light.